As is known, a clutch release bearing generally comprises an operating member controlled by an actuating member, in particular a clutch release fork, a drive member axially attached to the operating member and responsive to axial displacement of the operating member for coacting with the clutch release mechanism which is normally a diaphragm spring.
The present invention relates more particularly to such clutch release bearings in which the operating member comprises an axial sleeve which is received on a guide member and a transverse flange for bearing against the actuating member on one side and against the drive member on the other, opposite side. For construction requirements the sleeve and the flange must be at least partly made of metal, for example, as regards the sleeve, to provide sufficient mechanical strength or the desired coefficient of friction relative to the guide member, and as regards the flange, to have a sufficient wear resistance owing to contact with the actuating member.
As for the drive member, it may, as is common, comprise a ball bearing having one race which bears axially, directly or indirectly, against the operating member, and another race which defines the active or drive portion of the drive member must bear at its free end against the clutch release mechanism.
A difficulty arises in the construction of such clutch release bearings when the actuating member and the clutch release mechanism are axially distant from each other, the flange of the operating member against which the actuating member bears must be axially distant from the drive portion of the drive member which must bear against the clutch release mechanism.
A considerable axial distance between the flange of the operating member and the active end of the drive member must be taken up.
In French Pat. No. 72 03606, issued Sept. 29, 1972, a metal spacer is interposed axially between the flange of the operating member and the drive member. But with such a spacer which carries the drive member it is then necessary to insure axial positioning of the sleeve on the operating member. In this French patent the spacer is axially positioned by a bead formed in the sleeve which in practice must be made of sheet metal of sufficiently thin gage to permit the bead to be formed therein. Beside the fact that such a sheet metal sleeve may not be suitable for applications, the bead is not necessarily easy to form in the sidewall of the sleeve.
In French patent publication No. 2,454,017, published Apr. 9, 1980, a molded plastic spacer is fixed on the sleeve and the flange of the operating member. The construction is all the more complicated by the fact that the spacer is not separate from the sleeve and the flange, and various expedients must be taken to insure the securement of the drive member.